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Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Find broken symlinks
To understand why this is the equivalent of "find -L /path/to/search -type l, see http://ynform.org/w/Pub/FindBrokenSymbolicLinks or look at http://www.gnu.org/software/findutils/manual/html_mono/find.html

camelcase to underscore
For mac users !

Connect to SMTP server using STARTTLS
Allows you to connect to an SMTP server over TLS, which is useful for debugging SMTP sessions. (Much like telnet to 25/tcp). Once connected you can manually issue SMTP commands in the clear (e.g. EHLO)

Display two calendar months side by side
Displays last month, current month, and next month side by side.

autorun program when logon Windows XP

Search recursively to find a word or phrase in certain file types, such as C code
I have a bash alias for this command line and find it useful for searching C code for error messages. The -H tells grep to print the filename. you can omit the -i to match the case exactly or keep the -i for case-insensitive matching. This find command find all .c and .h files

check open ports without netstat or lsof

Update twitter via curl

Update your OpenDNS network ip
Intended for dynamic ip OpenDNS users, this command will update your OpenDNS network IP. For getting your IP, you can use one of the many one-liners here on commandlinefu. Example: I use this in a script which is run by kppp after it has successfully connected to my ISP: --- #!/bin/bash IP="`curl -s http://checkip.dyndns.org/ | grep -o '[[:digit:].]\+'`" PW="hex-obfuscated-pw-here" if [ "$IP" == "" ] ; then echo 'Not online.' ; exit 1 else wget -q --user=topsecret --password="`echo $PW | xxd -ps -r`" 'https://updates.opendns.com/nic/update?hostname=myhostname&myip='"$IP" -O - /etc/init.d/ntp-client restart & fi --- PS: DynDNS should use a similar method, if you know the URL, please post a comment. (Something with members.dyndns.org, if I recall correctly)


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